$\dfrac{4}{3} - \dfrac{5}{10} = {?}$
$ = {\dfrac{4 \times 10}{3 \times 10}} - {\dfrac{5 \times 3}{10 \times 3}} $ $ = {\dfrac{40}{30}} - {\dfrac{15}{30}} $ $ = \dfrac{{40} - {15}}{30} $ $ = \dfrac{25}{30}$